Patent GB-276435-A (GB)
Title: Improvements in process for manufacturing vulcanization accelerators and products obtained therefrom
IPC: C08K5/00
Filed: 1926-05-28
Abstract: 276,435. Marks, E. C. R., (Du Pont de Nemours & Co., E. 1.). May 28, 1926. Vulcanizing compositions.-An accelerator for rubber vulcanization is prepared by the interaction of an aliphatic or aromatic aldehyde, an amine, and carbon disulphide, or of an anhydroaldehyde-amine with carbon disulphide, or of an aldehyde with the substituted ammonium salt of a mono-substituted dithiocarbamic acid. The molecular proportions of aldehyde, amine, and carbon disulphide may be 1 : 1 : 1 or 2 : 1: 1 or 2: 2: 1 or 4 : 2 : 1. When equimolecular amounts are used, the product is probably an alkyl (or aryl) a - mercapto - alkyl-dithio-carbamolactone. With half the amount of carbon disulphide, substituted carbothialdines, or more correctly N-substituted. (a1)-thion-hexahydrothio-(ab1 diazoles are obtained. Suitable aldehydes are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde, &c., while the amine may be methylamine, ethylamine, hydroxy-ethylamine, n- or iso-propylamine, n or iso-butylamine, aniline, o or p toluidine, &c. In examples -(1) Two moles of butyraldehyde and one mole of CS2 are mixed and treated with two moles of hydroxy-ethylamine first at 25‹ C. and then at 80‹ C. The resulting heavy oil may be added in the proportion of 0.75 part to 50 parts each of smoked sheets and amber crepe and 6 parts each of zinc oxide and sulphur, the mixture being steamed at 20 lbs. pressure for 45 minutes. (2) A mixture of two moles of benzaldehyde and one of CS2 is treated with two moles of methylamine first at 25-30‹ C. and then at 60‹ C. On cooling, white needles are precipitated, and washed successively with sodium bisulphite solution and water. (3) Two moles of acetaldehyde are; mixed with one mole of CS2 and cooled in an ice bath. Two moles of aniline are stirred in, and the mixture heated to 70‹ C. The product of this or of the preceding Example may be employed in a rubber mixture similar to that in the first Example, the mixture being cured at 40 lbs. steam pressure. (4) Two moles of butyraldehyde and one of CS2 are mixed with two of primary nbutylamine, and heated to 100‹ C. The product is an oil which may be used directly or mixed with clay or zinc stearate, and may be incorporated in a mixture analogous to that in the first Example, the mixture being cured at 121.5‹ C. (5) One mole of aniline is mixed with two moles of butyraldehyde at about 50‹ C., and then heated to 120‹ C., the water being evaporated in vacuo. After cooling to 30‹ C., one mole of CS2 is added, and the mixture heated in a closed vessel to 80‹ C. The product is subjected to vacuum treatment and may be added in the proportion of 0.375 part to 50 parts each of smoked sheets and amber crepe, 3 of zinc oxide, and 3.5 of sulphur; the mixture is cured at 130‹ C. (6) Equimolecular proportions of butyraldehyde and methylamine are mixed under pressure to prevent volatilization of intermediate compounds; a molecular proportion of CS2 is then added. The reaction product may be added in the proportion of 0.7 part to 50 parts each of smoked sheets and amber crepe, 3 of zinc oxide, and 3.5 of sulphur, and the mixture cured at 20 lbs. pressure. (7) A little over 4 moles of butyraldehyde are heated with two moles of aniline, the water formed is removed, and one mole of CS2 is added. The resulting oil may be employed in the proportion of 0.735 part in a rubber mixture of the above kind, which is steamed at 25 lbs. Compounds obtained from other combinations of particular aldehydes and primary amines and carbon bisulphide are also specified.